ByteArray should not be considered iterable

[zhumin8]

When trying to write a ByteArray field with spring data, fails with error.

When binding collections, Parameters.in(SpannerType.of(Type.array(...))) must be used.; nested exception is com.google.cloud.spanner.r2dbc.BindingFailureException: When binding collections, Parameters.in(SpannerType.of(Type.array(...))) must be used.))

This exception is thrown from IterableBinder.java. ByteArray should not be considered iterable. It should convert to equivalent of a single object.

For reference, we avoid considering ByteArray an iterable in Spring Data spanner with a workaround here.